The hatch and presence of Mahogany (Genus Paraleptophlebia) is totally overshadowed by those of Pale Morning Dun as they share just about the same hatch period. The Mahogany duns surely are beautiful mayflies too. Trout may not particularly key only on them but I often find them in stomach samples. It doesn't hurt to keep some of Mahogany patterns in your fly boxes to show something different to the trout.

Late June at DePuy Spring Creek

From a stomach pump of trout caught during PMD hatch at Armstrong's.
Observe the mix of PMD and Mahogany duns.

Seasonal Importance:

Mahogany Dun hatches are most common in late June to sometime into July, just like the prime hatches of PMD. The nymphs are classified as crawlers.

Pheasant Tail Mayfly Cripple – Mahogany

Hook: Standard dry #14, 16, 18

Thread: 8/0 or smaller, brown or dark brown

Ribbing: Gold or copper fine wire

Tail & Abdomen: Natural or dyed brown pheasant tail

Wing: Dun or dark-dun CDC

Hackle: Brown

Thorax: Superfine dub, Mahogany brown

Sawyer PT – Mahogany

Hook: Standard dry #14, 16, 18

Thread: 8/0 or smaller, brown or dark brown

Ribbing: Copper fine wire

Tail & Abdomen & Wing-pad: Natural or dyed brown pheasant tail

Abdomen Hackle: Brown, trimmed

Thorax: Copper fine wire

How to Fish:

Trailing these two is very effective, or use them by trailing and making combinations with PMD patterns.